Assessing the Clinical Applicability of Population Specific Bolton’s Norms

Introduction: Bolton’s norms are an essential parameter used in orthodontic diagnosis to evaluate the tooth size discrepancy. However, these norms have been established for Caucasian population and population variations necessitates the evaluation of these norms on Haryana population. Aim: The aim of the present study was to determine Bolton’s ratios for Haryana population, compare them with original Bolton’s ratios and determine the clinical significance of these differences. Materials and Methods: The study sample consisted of study casts of 100 subjects in the age range of 18-25 years, all belonging to Haryana population, having a full complement of teeth with Angle’s Class I molar and canine relationship, proper intercuspation, normal overjet and overbite and minimal crowding and spacing. Tooth dimensions were measured using digital vernier caliper (accurate to 0.01 mm) and Bolton’s anterior and overall ratio was calculated. Unpaired t-test was used to determine statistical differences between sexes and Single sum t-test was used to determine difference between population groups. Results: Bolton’s anterior and overall ratio norms for Haryana population sample were found to be 77.89%+0.23 and 91.45%+1.77 respectively. Statistically significant differences were found in the anterior ratio of Haryana population and Bolton’s original values but both anterior and overall ratio of Haryana population lie well within the 1 standard deviation of original Bolton’s norms. Conclusion: Clinical relevance of differences in Bolton’s norms established for Haryana population was not found in spite of statistically significant differences from original Bolton’s norms. Hence, original Bolton’s norms for anterior and overall ratio can be used for Haryana population.